An optional HTML tag that is used to specify information about a web document. Some search engines use 'spiders' to index web pages. These spiders read the information contained within a page's META tag. So in theory, an HTML or web page author has the ability to control how their site is indexed by search engines and how and when it will 'come up' on a user's search. The META tag can also be used to specify an HTTP or URL address for the page to 'jump' to after a certain amount of time. This is known as Client-Pull. What this means, is a web page author can control the amount of time a web page is up on the screen as well as where the browser will go next.